Run-time permission helper. Dangerous permissions https://stackoverflow.com/a/36937109/5710872

PermissionHelper.java

package com.qamar.kust.ui.helpers;

import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v4.content.PermissionChecker;

/**
 * Created by Qamar Abbas KUST on 12/11/2017.
 */

public class PermissionHelper {

    PermissionCallback permissionCallback;
    int requestCode;
    String[] requiredPermission;
    Activity context;

    public PermissionHelper(Activity context, int requestCode, String[] requiredPermission, PermissionCallback permissionCallback) {
        this.context = context;
        this.requestCode = requestCode;
        this.requiredPermission = requiredPermission;
        this.permissionCallback = permissionCallback;
    }

    public PermissionHelper request() {
        if (isPermissionGranted(context,requiredPermission)){
            permissionCallback.granted();
            return this;
        }


        ActivityCompat.requestPermissions(context, requiredPermission, requestCode);
        return this;
    }

    public static boolean isPermissionGranted(Context context, String... requiredPermission){
        for (String permission: requiredPermission){
            if (ContextCompat.checkSelfPermission(context,permission)!= PermissionChecker.PERMISSION_GRANTED){
                return false;
            }
        }
        return true;

    }
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        if (this.requestCode == requestCode) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                permissionCallback.granted();
            } else {
                permissionCallback.failed();

            }
        }
    }

    public interface PermissionCallback {
        void granted();

        void failed();

    }
}

Usage

                        permissionHelper = new PermissionHelper(context
                                , 22
                                , readExternalStorage
                                , new PermissionHelper.PermissonCallback() {
                            @Override
                            public void Granted() {
                                onImageOptionSelected(imageOptionSelected);
                            }

                            @Override
                            public void Failed() {
                                MyApp.showToast(getString(R.string.msg_permission_read_storage));
                            }
                        }).request();

and
It handle never ask again by

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        mPermissionHelper.onRequestPermissionsResult(requestCode, permissions, grantResults);

    } ```